Harnessing the winds of change

A five-minute primer on an issue making headlines

Lamma Island's wind turbine was officially launched last week, even though it's been spinning there for several months.

Why the big deal?

From last week, the turbine officially started supplying electricity to local homes. It was erected in September, and has been on trial since then. Hongkong Electric also revealed that the enormous, electricity-generating wind turbine in Tai Ling, the first of its kind in Hong Kong, had been given a name. After receiving 3,800 submissions, the company chose 'Lamma Winds'.

So, what does it actually do?

The $15 million, 800kW turbine is supposed to generate about 1 million units of electricity a year, save 350 tonnes of coal and produce enough energy for 250 homes.

Will it power specific homes on Lamma?

No. The electricity goes into Hongkong Electric's power grid on Lamma, which then distributes it to homes across the island.

It's fairly humongous, and strangely hypnotic. Are we going to see any more of them?

I guess if Lamma-ites can get used to three huge power station chimneys on their horizon, they barely notice a graceful, 71-metre tall, gleaming, white turbine with three whirling 52-metre blades. There's been talk of a wind farm, with 50 massive turbines the height of Jardine House being built on Ninepin Island, off Sai Kung, but it's still very much in the planning stages. Hongkong Electric has also mentioned it may also get involved in building offshore wind farms because there's so little land.

How do they work?

There are three parts in a wind turbine: the tower, the blades, and the nub behind the blades called the nacelle, which houses a generator. Wind turns the blades, which are attached to a shaft that runs into a gearbox. This gearbox increases the final shaft speed to the generator, which produces AC (alternating current) electricity. The Lamma turbine automatically starts up when wind speeds are between 3 and 25 metres per second. More energy can be produced with bigger blades.

Bet a lot of electricity gets generated in typhoons!

Not exactly. When the wind speed gets too high, a braking system within the nacelle will slow down or stop the turbine.

Is it a new invention?

Europe and the US have been putting up wind turbines for many years, and windmills have been used for centuries.